using System;
using System.Collections.Generic;

namespace lab10B
{

    public static class FunctionGenerationAndUsage
    {
        public delegate double Fun1(double a, double b);
        public delegate T Fun2<T>(T a, T b);
        public delegate double Fun3(double x);
        public delegate double Fun4(Point2D p1, Point2D p2);
        public delegate int[] Fun5(int[] tab);

        public static Fun2<double> NilpotentMinimumGeneration()
        {
            return delegate (double a, double b)
            {
                if (a + b > 1) return Math.Min(a, b);
                else return 0;
            };
        }
        public static List<T> ScanList<T>(Fun2<T> f, params T[] tab)
        {
            if (tab.Length == 0) return null;
            List<T> l = new List<T>();
            T element = tab[0];
            l.Add(element);
            for (int i=1;i<tab.Length;i++)
            {
                element = f(element,tab[i]);
                l.Add(element);
            }
            return l;
        }
        public static Fun3 PolynomalFunction(Fun3 f, double[] tab)
        {
            return delegate (double x)
            {
                double sum = 0.0, temp = 1;
                sum += temp * tab[0];
                for (int i = 1; i < tab.Length; i++)
                {
                    temp *= f(x);
                    sum += temp * tab[i];
                }
                return sum;
            };
        }
        public static double Integral(double a, double b, double n, Fun3 f)
        {
            double sum = 0.0;
            double average;
            double przedzial_len = (b - a) / n;
            double miejscenaosi = a;

            for (int i=0;i<n;i++)
            {
                average = (f(miejscenaosi) + f(miejscenaosi + przedzial_len))/2;
                sum += przedzial_len * average;
                miejscenaosi += przedzial_len;
            }
            return sum;
        }

        public static Fun4 ChebyshevDistance()
        {
            return delegate (Point2D p1, Point2D p2)
            {
                double max = Math.Abs(p1.X - p2.X);
                if (Math.Abs(p1.Y - p2.Y) > max) max = Math.Abs(p1.Y - p2.Y);
                return max;
            };
        }

        public static Point2D SmallestEnclosingBall(List<Point2D> l, Fun4 f)
        {
            double min_dist = double.MaxValue;
            double max_dist;
            Point2D p = l[0];
            //for (int i=0;i<l.Count;i++)
            //{
            //    for (int j = 0; j < l.Count; j++)
            //        if (i != j && f(l[i], l[j]) < min_dist)
            //        {
            //            min_dist = f(l[i], l[j]);
            //            p = l[i];
            //        }
            //}
            foreach (Point2D punZew in l)
            {
                max_dist = 0.0;
                foreach (Point2D punWew in l)
                {
                    if (f(punZew, punWew) > max_dist) max_dist = f(punZew, punWew);
                }
                if (max_dist<min_dist)
                {
                    min_dist = max_dist;
                    p = punZew;
                }

            }
            return p;
        }

        public static Fun5 ReversedPascalTriangleGeneration(int a) //public delegate int[] Fun5(int[] tab);
        {
            return delegate (int[] tab)
            {
                int[] newtab = new int[tab.Length - 1]; //

                for (int i = 0; i < tab.Length - 1; i++)
                {
                    newtab[i] = tab[i] + tab[i + 1] + a;
                }

                return newtab;
            };
        }
        public static void ReversedTriangleGeneration(Fun5 f,int[] tab)
        {
            while (tab.Length>=1)
            {
                Program.PrintArray(tab);
                tab = f(tab);
            }
        }

    }
}